1. Field of the Invention
The present invention relates to a tilt lock structure of a tiltable driver's cabin for used in a work vehicle.
2. Description of the Related Art
Conventionally, there is known a work vehicle having a driver's cabin constituted tiltable, the driver's cabin being also called a cab, a canopy, a cabin, and the like. With this constitution, when the tiltable driver's cabin is tilted up, since a working space around an engine disposed below the driver's cabin can be released, a maintenance and check job to the engine and the like can be easily performed.
The driver's cabin, which is tilted up or down, has a heavy weight due to various devices and the like disposed therein. Accordingly, a cylinder unit such as a gas spring and the like is interposed between the driver's cabin and a vehicle body frame so that a tilt operation can be performed to the driver's cabin by the extending and contracting action of the cylinder unit. Otherwise, the tilt operation can be manually performed to the driver's cabin using the extending/contracting action of the cylinder unit as an auxiliary power.
In this type of the constitution capable of tilting the driver's cabin, a driver's cabin lowering motion prevention device is added to prevent a danger that the driver's cabin is lowered when the cylinder unit fails, and the like. An ordinary driver's cabin lowering motion prevention device includes a constitution for preventing the contraction of an extended piston rod by inserting a stopper pin into a through hole formed to the piston rod, a constitution for preventing the contraction of an extended piston rod by disposing brackets to the outer periphery of a cylinder tube and to the front end side of the piston rod and interposing a stopper member between both the brackets (refer to Japanese Patent Application Laid-Open (JP-A) No. 10-86859) and the like.
However, in these lowering motion prevention devices, the stopper pin must be inserted or the stopper member must be interposed between the brackets after the piston rod of the cylinder unit is extended. Further, since these lowering motion prevention devices are disposed to a side lower portion of a driver's cabin, when, for example, a driver manually tilts up the driver's cabin from a front side of the driver's cabin, the driver must go to a side portion of the driver's cabin and operate the lowering motion prevention device.
Moreover, each time a worker confirms whether or not the lowering motion prevention device is operated, the driver must go to the side portion of the driver's cabin for the confirmation. Accordingly, when the worker wants to confirm the operating state of the lowering motion prevention device while he or she performs the maintenance and check of the engine and the like, he or she must interrupt the maintenance and check job once.